package cn.com.oceansoft.nos.common.util;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * 线程相关的Utils函数集合.
 *
 * @author chenw
 */
public class ThreadUtils {

    /**
     * sleep等待,单位毫秒,忽略InterruptedException.
     */
    public static void sleep(long millis) {
        try {
            Thread.sleep(millis);
        } catch (InterruptedException e) {
            // Ignore.
        }
    }

    /**
     * 按照ExecutorService JavaDoc示例代码编写的Graceful Shutdown方法.
     * 先使用shutdown尝试执行所有任务.
     * 超时后调用shutdownNow取消在workQueue中Pending的任务,并中断所有阻塞函数.
     * 另对在shutdown时线程本身被调用中断做了处理.
     *
     * @param shutdownNowTimeout TODO
     */
    public static void gracefulShutdown(ExecutorService pool, int shutdownTimeout, int shutdownNowTimeout, TimeUnit timeUnit) {
        pool.shutdown(); // Disable new tasks from being submitted
        try {
            // Wait a while for existing tasks to terminate
            if (!pool.awaitTermination(shutdownTimeout, timeUnit)) {
                pool.shutdownNow(); // Cancel currently executing tasks
                // Wait a while for tasks to respond to being cancelled
                if (!pool.awaitTermination(shutdownNowTimeout, timeUnit)) {
                    System.err.println("Pool did not terminate");
                }
            }
        } catch (InterruptedException ie) {
            // (Re-)Cancel if current thread also interrupted
            pool.shutdownNow();
            // Preserve interrupt status
            Thread.currentThread().interrupt();
        }
    }

    /**
     * 直接调用shutdownNow的方法.
     */
    public static void normalShutdown(ExecutorService pool, int timeout, TimeUnit timeUnit) {
        try {
            pool.shutdownNow();
            if (!pool.awaitTermination(timeout, timeUnit)) {
                System.err.println("Pool did not terminate");
            }
        } catch (InterruptedException ie) {
            Thread.currentThread().interrupt();
        }
    }

    /**
     * 自定义ThreadFactory,可定制线程池的名称.
     */
    public static class CustomizableThreadFactory implements ThreadFactory {

        private final String namePrefix;
        private final AtomicInteger threadNumber = new AtomicInteger(1);

        public CustomizableThreadFactory(String poolName) {
            namePrefix = poolName + "-";
        }

        public Thread newThread(Runnable runable) {
            return new Thread(runable, namePrefix + threadNumber.getAndIncrement());
        }
    }
}
